It is well known to prepare polyurethane foundry binders by reacting a phenolic resin and an organic polyisocyanate in the presence of a urethane promoting catalyst. See for example U.S. Pat. Nos. 3,485,797; 3,676,392; and 3,409,579. These patents and others clearly indicate that various solvents must be used in order to facilitate the mixing of the components and the reaction between the phenolic resin and organic polyisocyanate.
In particular, U.S. Pat. No. 3,676,392 relates to a no-bake process for preparing foundry shapes wherein a liquid urethane promoting catalyst is used to facilitate the reaction between the phenolic resin and organic polyisocyanate. This patent discloses that butyl cellosolve (butyl acetate) and cellosolve acetate (ethylene glycol mono methyl ether acetate) can be used as solvents with appropriate co-solvents for the phenolic resin.